A fluid-structure interaction problem requires the solution of the coupled equations of both the fluid and the structure. This can be computationally highly intensive and extremely time-costly depending on the complexity of the phenomena to be predicted. Such is the case for structures such as the flap track fairing (FTF). Their behavior is geometrically highly nonlinear and depends on the source of excitation. FTFs withhold the mechanisms of deployment of flaps and their shape is conceived not to degrade wing performances. They are connected to the primary structure through mechanisms which are an important source of nonlinearities such as contact or friction. Depending on their position, they can be exposed to high vibrations induced from the engine efflux for short periods of time during take-off. Failure to predict these vibration problems in the design phase causes the necessity for reinforcement and requires servicing actions with aircraft grounding for repair or replacement of the structure. There is therefore a strong need to develop a method of load prediction. This paper shows that a combination of structural and aerodynamic reduced order models, interpolation techniques, and an efficient aero-structure data exchange could provide a fast method to estimate non-linear fluid structure interaction during transient response.